[xaco]

Hello,i would like to be able to melt steel and sandcast it to make some 1 pound stamping dies... i saw some Acetylene-Atmospheric air systems that can burn up to4770°F (2632°C).but tips seam to be narrow....http://www.riogrande.com/MemberArea/...612558=500+109 ...can a piece of steel ,size about 2x2x2 inches be melted with torch and sandcasted? anyone have any experience?

[metalcaster4jc]

Steel in the molten state is very hungry for gases; oxygen and nitrogen get sucked up quickly and end up in the casting. There are some alloys added to the molten steel prior to casting to "tie up" the gases so that the castings do not look like swiss cheese (aluminum for the oxygen and zirconium or titanium for the nitrogen). These alloys are added just prior to pouring, and they will chill the metal when added, so you have to superheat which makes everything more reactive. After you have taken care of the gases absorbed when melting, you then have to deal with the gases absorbed while pouring into the sand mold and then liberated by what ever binder that you are using. Add to that the fact that molten steel shrinks during solidification where your casting yield is about 50% or less of your pour weight. Also depending upon the binder used in your sand mold, steel will react with the sand and becomes burned onto the casting. In short and to wit you have major obstacles to overcome with your idea if you want decent castings. If it were easy everyone could do it.

[DMF_TomB]

i have melted up to 100 lbs on cast iron using a furnace that burned kerosene. it used hot exhaust to preheat kerosene to it's boiling point.

1) above 2600 degrees F (white heat) i needed to make foundry tongs that could grab and lock on crucible and hoist it up with battery drill powered hoist on a hoist trolley that rolled on 16 foot I beam, it was needed so I could let go and back away from heat radiating from crucible. to get an ideal the leather welding jacket and apron i wore i could see steam from leather drying. you literally have less than a minute to open furnace, grab and hoist hot crucible and roll it away from hot furnace which is radiating a huge amount of heat. this is with furnace just Outside a building, another small bronze melting furnace I had IN the building when furnace opened heat shattered the ceiling light bulbs to get an ideal of heat radiating from hot open furnace.

2) crucible tongs was counter weighted. it was needed as without it was hard to push on handle to tilt crucible to pour iron from weight of liquid iron. splashing was hard to control as once metal flowed tens of pounds of liquid metal was moving and it is hard to pour steady.

3) i have poured cast iron into cast iron molds that were covered with carbon soot from acetylene torch. but i speak from experience the slightest drop of water in mold and molten cast iron will explode like a fireworks burst with sparks going over 10 feet from center. if mold is not thick enough liquid cast iron will stick to cast iron mold.

4) sand used for sand casting must be pure high temp type. Some sand melting and sticking to cast iron occurs at hot spots.

5) the regenerative or using hot exhaust to preheat and boil fuel must be thought out. i once got kerosene vapor so hot and at a higher than fuel pump pressure it went back towards pump and started leaking out a pressure gage (with soldered fitting inside it). even though i turned pump off and fan blower off the "kerosene steam" from boiler which was hissing for many minutes could have exploded easily. even with me backing up literally the whole building could have blown up. if you ever think something will just fireball and not explode try filling a balloon with a oxygen AND acetylene mix and popping it with torch flame. i speak from experience wear ear plugs and face shield and if balloon is big enough it will knock you off your feet.

melting steel is even more difficult as crucible must be able to hold extra hot liquid steel as by the time you pour it it is getting cooler. not hot enough and difficult to completely fill mold.

for very small castings i would look into jewelry spin casting but usually it is brass, bronze, sliver which is lower temp than cast iron or steel. or look into thermite for making small steel castings. torch melting 2" by 2 by 2 cube of steel takes a lot of heat. try oxyactelyene welding 3/4" thick steel plate first to get an ideal of heat needed to melt steel

[xaco]

wow,thanx for elaborated answers,,steel is not an option any more,you scared me enough....so,what material would be an alternative? i have small gas furnace wits fan,i have small coke furnance that i never used and i dont want cos i dont have open space, and i prefer butan+compressed ait open torch melting.... i have bronze (10% Sn) but it looks soft, i wanna cast stamping male die (max2x2x2 inches) and if posible "sink " it in some softer material,like aluminium... what woudl be the hardest material for that taht can be sand casted or even better,lost wax vacuum casted ?